1. College of Material Science & Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China
2. School of Mechanical, Electrical & Information Engineering Shandong University Weihai Weihai 264209 P. R. China
3. Key Laboratory of Rubber‐Plastics Ministry of Education Qingdao University of Science and Technology Qingdao 266042 P. R. China